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How Do You Write an SQL Case Statement With Multiple Conditions?

Posted on 2014-02-10
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Last Modified: 2014-02-16
I am wring an SQL case statement using multiple conditions with string concatenation.  My case statement is not working properly.  

Here is the code:
ErrorDescription = CASE WHEN LTRIM(RTRIM(ISNULL(EventIdentifier, ''))) = ''
                                        THEN 'EventIdentifier Missing, '
										WHEN LEN(LTRIM(RTRIM(PrimaryDrugNDC))) > 11
											   THEN 'PrimaryDrugNDC Too Long, '
										WHEN LTRIM(RTRIM(ISNULL(SecondaryDrugName, ''))) = ''
											   THEN 'SecondaryDrugName Missing, '
										WHEN LEN(LTRIM(RTRIM(SecondaryDrugName))) > 150
											   THEN 'SecondaryDrugName Too Long, '
										WHEN LTRIM(RTRIM(ISNULL(SecondaryDrugNDC, ''))) = ''
											   THEN 'SecondaryDrugNDC Missing, '
						ELSE ''
                 END,

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Thanks,

Dan
0
Comment
Question by:danielolorenz
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13 Comments
 
LVL 5

Expert Comment

by:dannygonzalez09
ID: 39847955
what is the issue.. Sry, but i don't see any string concatenations in the case
0
 
LVL 16

Expert Comment

by:Surendra Nath
ID: 39847963
My case statement is not working properly.

can you tell us what is happening currently with your case statement and what exactly you need it to happen?
0
 

Expert Comment

by:cyimxtck
ID: 39847974
create table t_value
(
      x            tinyint                  
)

insert into t_value
(
      x
)

values
(
 3
)

select
  case
  when x = 2            then 'two'
  when x = 3            then 'three'
  end
from
  t_value
0
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Author Comment

by:danielolorenz
ID: 39847986
The case statement is returning blanks.

Here is an example of my case statement when I use string concatenation:

Case Statement:
ErrorDescription = CASE WHEN LTRIM(RTRIM(ISNULL(EventIdentifier,
                                                              ''))) = ''
                                        THEN 'EventIdentifier Missing, '
                                   END
                + CASE WHEN LEN(LTRIM(RTRIM(EventIdentifier))) > 20
                       THEN 'EventIdentifier Too Long, '
                  END
                + CASE WHEN LTRIM(RTRIM(ISNULL(EventDate, ''))) = ''
                       THEN 'EventDate Missing, '
                  END
                + CASE WHEN LEN(LTRIM(RTRIM(EventDate))) > 25
                       THEN 'EventDate Too Long, '
                  END,

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0
 

Author Comment

by:danielolorenz
ID: 39847991
I want to retrieve an ErrorDescription column results.

For Example: "EventIdentifier Too Long, EventDate Missing,"

Dan
0
 

Expert Comment

by:cyimxtck
ID: 39847995
The case statement will end upon matching one item...
0
 

Expert Comment

by:cyimxtck
ID: 39848008
What you could do here is create a table with all the possible options and populate it with a dictionary pair:

x       Y
val     3

Select those values out in an inner join to the Y value, retrieve the X value and concatenate them.
0
 
LVL 69

Expert Comment

by:Scott Pletcher
ID: 39848107
Your last post is very close.  I suggest using leading ", " instead of trailing, as it allows a standard SUBSTRING to give a final result:

 ErrorDescription = SUBSTRING(
                    CASE WHEN LTRIM(RTRIM(ISNULL(EventIdentifier, ''))) = ''
                         THEN ', EventIdentifier Missing' ELSE ''
                    END
                  + CASE WHEN LEN(LTRIM(RTRIM(EventIdentifier))) > 20
                         THEN ', EventIdentifier Too Long' ELSE ''
                    END
                  + CASE WHEN LTRIM(RTRIM(ISNULL(EventDate, ''))) = ''
                         THEN ', EventDate Missing' ELSE ''
                    END
                  + CASE WHEN LEN(LTRIM(RTRIM(EventDate))) > 25
                         THEN ', EventDate Too Long' ELSE ''
                    END
                    , 2, 8000),
0
 
LVL 69

Expert Comment

by:Scott Pletcher
ID: 39848113
For example:


SELECT  
    EventIdentifier,EventDate,              
 ErrorDescription = SUBSTRING(
                    CASE WHEN LTRIM(RTRIM(ISNULL(EventIdentifier, ''))) = ''
                         THEN ', EventIdentifier Missing' ELSE ''
                    END
                  + CASE WHEN LEN(LTRIM(RTRIM(EventIdentifier))) > 20
                         THEN ', EventIdentifier Too Long' ELSE ''
                    END
                  + CASE WHEN LTRIM(RTRIM(ISNULL(EventDate, ''))) = ''
                         THEN ', EventDate Missing' ELSE ''
                    END
                  + CASE WHEN LEN(LTRIM(RTRIM(EventDate))) > 25
                         THEN ', EventDate Too Long' ELSE ''
                    END
                    , 2, 8000)
FROM (
    SELECT '' AS EventIdentifier, 'this is toooooo long for the dateeeeeeeeeeeeeeeeeeeee.' AS EventDate UNION ALL
    SELECT 'this is a veryyyyyyy longgggg valueeeeeee.', '' UNION ALL
    SELECT NULL, NULL UNION ALL
    SELECT 'these values should', 'be just right.'
) AS test_data
0
 
LVL 69

Expert Comment

by:Scott Pletcher
ID: 39848119
CORRECTION:

SUBSTRING(..., 3, 8000)
0
 

Accepted Solution

by:
danielolorenz earned 0 total points
ID: 39850520
I added an ELSE '' to the CASE STATEMENTS and it works fine now.

This is the solution I was looking for:
               ErrorDescription = CASE WHEN LEN(LTRIM(RTRIM(EventIdentifier))) > 20
                                                         THEN 'EventIdentifier Too Long, '
                                                         ELSE ''
                                                  END
                                                + CASE WHEN LTRIM(RTRIM(ISNULL(EventDate, ''))) = ''
                                                         THEN 'EventDate Missing, '
                                                         ELSE ''
                                                END
                                                + CASE WHEN LEN(LTRIM(RTRIM(EventDate))) > 25
                                                         THEN 'EventDate Too Long, '
                                                         ELSE ''
                                                END
                                                + CASE WHEN LEN(LTRIM(RTRIM(Username))) > 20
                                                         THEN 'Username Too Long, '
                                                         ELSE ''
                                                END
                                                + CASE WHEN LEN(LTRIM(RTRIM(FirstName))) > 50
                                                         THEN 'FirstName Too Long, '
                                                         ELSE ''
                                                END
                                                + CASE WHEN LEN(LTRIM(RTRIM(LastName))) > 50
                                                            THEN 'LastName Too Long, '
                                                            ELSE ''
                                                END
                                                + CASE WHEN LEN(LTRIM(RTRIM(Location))) > 100
                                                            THEN 'Location Too Long, '
                                                            ELSE ''
                                                END
                                                + CASE WHEN LEN(LTRIM(RTRIM(InterventionName))) > 150
                                                            THEN 'InterventionName Too Long, '
                                                            ELSE ''
                                                END
                                                + CASE WHEN LTRIM(RTRIM(ISNULL(Accepted, ''))) = ''
                                                         THEN 'Accepted Missing, '
                                                         ELSE ''
                                                END
                                                + CASE WHEN LEN(LTRIM(RTRIM(Accepted))) > 1
                                                         THEN 'Accepted Too Long, '
                                                         ELSE ''
                                                END
                                                + CASE WHEN LTRIM(RTRIM(ISNULL(PrimaryDrugName, ''))) = ''
                                                         THEN 'PrimaryDrugName Missing, '
                                                         ELSE ''
                                                END
                                                + CASE WHEN LEN(LTRIM(RTRIM(PrimaryDrugName))) > 150
                                                         THEN 'PrimaryDrugName Too Long, '
                                                         ELSE ''
                                                END
                                                + CASE WHEN LEN(LTRIM(RTRIM(PrimaryDrugNDC))) > 11
                                                         THEN 'PrimaryDrugNDC Too Long, '
                                                         ELSE ''
                                                END
                                                + CASE WHEN LEN(LTRIM(RTRIM(SecondaryDrugName))) > 150
                                                         THEN 'SecondaryDrugName Too Long, '
                                                         ELSE ''
                                                END
                                                + CASE WHEN LEN(LTRIM(RTRIM(SecondaryDrugNDC))) > 11
                                                         THEN 'SecondaryDrugNDC Too Long, '
                                                         ELSE ''
                                                END
                                                + CASE WHEN LEN(LTRIM(RTRIM(Comments))) > 2000
                                                         THEN 'Comments Too Long, '
                                                         ELSE ''
                                                END
                                    + '::END',
0
 
LVL 69

Expert Comment

by:Scott Pletcher
ID: 39850645
Exactly the way I did in the code I posted.
0
 

Author Closing Comment

by:danielolorenz
ID: 39862463
Great
0

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